NASA Aims to Blast Comet to Study Solar System

By REUTERS

Published: January 17, 2001

SANTIAGO, Chile - NASA scientists aim to blast a comet with a copper projectile to learn about the formation of the solar system as part of a $270 million project funded by NASA, the head of the project said on Tuesday.

The project, called Deep Impact and which will cause an explosion capable of destroying a small town, would be the first space mission to probe inside a comet, whose primitive core could reveal clues about evolution of the solar system.

``All our studies of comets look only at the surface layer. Our theoretical models tell us the surface has changed, and only the interior has the original composition. So our main goal is to compare the interior with the surface,'' the project's director, Michael A'Hearn, told reporters.

Scientists chose copper, Chile's No. 1 export, because it is less likely to interfere with the materials inside the crater.

In January 2004, a rocket would launch from Cape Canaveral, Florida, a spacecraft that would orbit the sun. In July 2005 the spacecraft would separate from a battery-powered, copper projectile that would collide with the comet 24 hours later at a velocity of 6 miles (10 km) per second.

It would produce a crater the width of a football field and up to 100 feet (30 meters) deep.

The spacecraft would observe the composition of the crater's interior, while telescopes on Earth would monitor the impact.

The project also aims to see if scientists can alter the orbit of a comet to protect the Earth from falling matter. The impact would alter the comet's orbit by a ``just barely measurable'' 62 to 620 miles (100 to 1,000 km), A'Hearn said.

The project would blast the Comet Tempel 1, which was discovered in 1867 and is a little less than Earth's distance from the sun, he said. It was chosen because its size, rotation and trajectory favor the project and because the collision would be observable from Earth.

In February, NASA will carry out a preliminary design review to see if the project can succeed.